References
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- Heslop , Harrison J.W. 1958 . Trees and shrubs on pitheaps . Vasculum , 43 : 14
- Richardson , J. A. , Burn , I. and Craig , G. 1987 . Long-term prospects for farm grassland and woodland on reclaimed coal spoil sites . Landscape and Urban Planning , 14 : 131 – 142 .